Toyota 2009 Tundra Owner's Manual page 313

If the ambient temperature drops while using the recirculated
n
air mode
The air intake mode automatically changes from recirculated air
mode to outside air mode after a few minutes.
To cancel this function:
Press and hold
To reactivate this function:
Turn the engine switch to the LOCK or ACC position.
Adjusting the position and opening and closing the air outlets
Driver side outlets
3-1. Using the air conditioning system and defogger
for longer than 2 seconds.
Direct air flow to the left or
right, up or down.
Turn the knob to open or close
the vent.
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